Dust trap window ventilator



April 18, 1944. I J. L. MOHUN DUST TRAP WINDOW VENTILATOR 2 Sheets-Sheet 1 Filed Sept. 7. 1940 w- Q Q INVENTOR. JO/ZFL L. Mo/izAz/z BY M firm 5 April 18, 1944. J. L. MOHUN DUST TRAP WINDOW VENTILA'IOR 2 Sheets-Sheet Filed Sept. 7. 1940 m w //..P g 111.. \Q\ .K%,/ Q

Q \Q mm km Q Q. 9% g I INVENTOR. Jo/z/z L. Mo/uuz Patented Apr. 18, 1944 UNITED STATES PATENT OFFICE 2,347,120 DUS-T TRAP WINDOW VENTILATOR John L. Mohun, Chicago, 111. Application September 7, 1940, Serial No. 355,843 1 13 Claims.

Myninvention relatestoventilators, and more particularly to window ventilators adapted .to thoroughlyclean'thegair passing through them.

An object of my invention is to provide an inexpensive adjustable window ventilator which will remove substantially all of the solid particles from the incoming air without seriously impeding the air flow, and which may be cleaned by ordinary implements. i

Another obj ectis to provide a window ventilator having adjustable means for cleaning and mixing fresh and recirculated air.

Another object ofmy invention is to provide a window ventilator from which cleaned fresh air may be supplied without causing objectionable drafts in the room. 5

These, and other objects of my invention, will become apparent from the following description and from the drawings in which Fig. 1 is a vertioal-cross-sectional view of the basic form of my invention as applied to a metal window. T

Fig. 2 is a horizontal sectional view taken along the line 22 of Fig. 1.

Figs. 3 and 4 are sectional views of a device adapted to maintain the movable scrubber in any desired position.

Fig. 5 is a vertical sectional viewof a modified form of my device particularly adapted for use in conjunction with storm windows.

Fig. 6 is another modification of my device having an attachmentfor cleaning and controlling recirculated air; and

Fig. 7 is asoniewhat diagrammatic view of a mechanism for holding the movable scrubbers in Z position.f r r My ventilator broadlyconsistsof an air filter maintained in position by a frame which also supports a movable scrubber. The scrubber cooperates with the filter to clean the air passing through the ventilator, and also serves as a dam per to contrpl'the volumeand direction of the incoming The frame is provided with a novel extension permitting the installation of my ventilator in jwin'diiw's of various width, and has all vital jointssealed against the entrance of dust and dirt. v

Referring to the drawings, Fig. 1 represents the basic form of myinvention, and is illustrated as applied to a metal window of the double hung type which comprises a lower sash rail I l, guides l2, a sill l3, and a sill flange l4 adapted to rest upon a stool 16. A filter I! is maintained in a substantially vertical position directly below, and in the same plane with the lower sash rail H, by

a frame, generally designated l8. The filter I? may be any one of, several types, for example, I have found that a type of filter known as Fiberglas to be satisfactory. This filter consists essen tially of a light fiber-board frame enclosing a mat of relatively coarse glass fibers which have been covered with an oily adhesive. Perforated metal plates 20 extend over both faces of this filter to maintain the wool mat in position. This forms a cartridge type of filter which may be easily removed and replaced when it has become saturated with dirt. My invention also contemplates the use of other types of filters such as those constructed of organic fibers or of metal, with or without oil or adhesive applied to the dust catching medium. I prefer, however, to provide my filter with face plates differing somewhat from those known to the prior art, my preferred form of face plate consisting of a series of spaced wires or bars l5 arranged to define relatively long and narrow rectangles, the axis of these rectangles being horizontal on one side and vertical on the other so that there are substantially no dead spots in the filter.

The frame It} comprises a lower cross-member l9 and side pieces 2|. The lower member has approximately H shaped cross-sections and rests upon the sill I3. More specifically this member consists of a vertical outer flange 22, a horizontal intermediate web 23 having a drain hole 25, a vertical upwardly extending inner flange 24, and a downwardly extending flange 2B offset 'outwardly from flange 24. The lower end of flange 26 is turned upwardly and inwardly and defines, in conjunction with a lip 27, a channeladaptedto receive a gasket 28 which may be of any desired material .such'as, felt,-rubber, or the like. How.- ever, I prefer to use a material known as Schlege l cloth, manufactured by The Schlegel Manufacturing Company, of Rochester, New Rork, which resembles'deep pile carpet, formed on a canvas base, which is in turn attached to a strip of light metal for ease of installation.

The vertical end sections'2l may be formed from either channel or H shaped sections having the same distance between flanges as the lower member 19. These members are attached to the extremities of the lower member and extend upwardly perpendicular thereto, forming a re-, ceiver for the cartridge type filter [1. These channels should be accurately shaped to prevent the entrance of dust into the room around the edges of the filter when in position within the receiver. As an alternative felt or similar material may be used to line the filter receiver Widths.

in order to provide a dust-tight assembly. If channel sections are used to form the end sections 2|, outwardly extending flanges 3| are provided on the back of each member, adapted to receive an extension 32 which may be of plywood or other suitable material.

A removable upper frame member 33 is also provided, fitting snugly over the upper ends of the end members 2| and the upper edge of the filter IT. The cross-section of this member is formed to not only fit over the filter, but also to cooperate with the lower sash rail ll to-form a dust-tight joint. In the form shown the member 33 is provided with a well 34 to receive a window flange 36 which is similar to flange 26 on the lower frame member IS. A gasket 31, similar to gasket 28, is also provided and cooperates with the member 33 to form a dusttight joint. A water shed 38 is formed integrally with the removable upper frame member 33, and

acts to prevent the entrance of excessive amounts of water into the filter. If desired a screen may be attached to the frame in front of the filter to prevent insects, paper and the like from blocking the filter.

As windows vary considerably in width, it is necessary to provide some means of adapting one size of ventilator to openings of varying I, therefore, provide rigid extensions 32, having a gasket 4| attached to one end and adapted to be received by the guides l2. The upper edges of the extension 32 may be shaped to cooperate with the lower sash rail II in a manner similar to the upper frame member 33,

or they may be provided with sections similar to member 33 in order to prevent passage of dust between the extensions and the window sash. The flange members 3| are provided with openings through which screws or bolts extend. The ventilator is positioned in the window by simply moving the extension 32 outwardly until it is in firm contact with the guide I 2, and fastening it in position by means of screws 35.

The inner portion of the flange 24 on the lower frame member I9 is provided with lugs 42 having aligned transverse openings. A rod 43 is journaled in these openings and supports a scrubber 44 which comprises a. rigid panel 45 of glass, wood, metal, resin, or similar material, and a layer of loosely woven hairy felt-like material 45, the latter being positioned on the inner side of the rigid panel in the path of the air entering the room through the filter. The hairy felt-like material 45 should preferably be formed with an irregular surface. I have found a loosely woven type of material known as Ozite to be particularly suited for this purpose. The fibers of this material are not all horizontal or parallel to the plane of the sheet, as is the case with felt and other materials. This increases the ability of the material to remove dust and other dirt particles from the: air and its use is therefore desirable.

End plates 41 are provided to limit the movement of the scrubber 44 and to confine the air. These end pieces may be formed from sheet metal and in their final form resemble a se ment of a circle having a radius slightly in excess of the height of the scrubber 44. One edge of each end plate is attached to one of the vertical frame members 2| in any desired manner, such as welding, and has an inwardly extending flange 48 on its inner edge to limit the inward movement of the scrubber 44. A curved inwardly extending flange 49 is provided along the top of each of the end plates 41 and is preferably corrugated, at least on its lower side, to engage a catch on the upper edge of the movable scrubber.

The hairy felt-like material 46 may be secured to the rigid panel in various Ways, as by wire stitching, gluing, riveting, or the like, but it is often convenient to secure the material in a removable manner. This is done by providing spring clips 51, attached to the inner bottom portion of the panel 45, which serve to hold the lower end of the felt-like material by direct engagement. The upper edge of the felt-like material is secured by the use of a channel shaped section of rubber 52 which fits over both the feltlike material 46 and the rigid panel 45. The rubber strip may be reinforced by internal spring clips if desired, and in addition to holding the material in place, serves to prevent the passage of air through the ventilator when the scrubber is swung to a vertical or closed position, the rubber strip acting as a gasket between the upper frame member 33 and the rigid panel 45.

The extremities of the rigid panel are preferably provided with a spring catch or clip, cooperating with the corrugations on the bottom of the flange 49 to maintain the scrubber in any desired position. A suitable metal clip adapted for this purpose is illustrated in Figs. 3 and 4, and consists primarily of an L shaped section of metal 53, one leg of which is secured to the rigid panel 45 with a rivet 53. The other leg of the section extends across the upper edge of the rigid panel 45, and has formed therein a sharp bend designated 54, which cooperates with the corrugations formed in the flange 49 to secure the scrubber in any desiredposition, the resilience of the catch maintaining engagement between the bend 54 and the corrugations. If desired an inwardly extending thumb piece 55 may be provided on the end of this clip whereby pressure of the thumb upon the thumb piece will disengage the catch from the corrugations.

Tests have shown that ordinary filters do not effectively stop all of the'ultra fine dust particles unless the filter is thick or dense. The use of filters of this nature is obviously objectionable as it greatly increases tlie'resistance of the filter to the passage of air and if used in a window ventilator, a fan would normally be required to draw air into the room. A' relatively thin filter, however, can be successfully used with my invention, for the fine dust particles passing through the filter will be brought into contact with the hairy felt-like surface of the scrubber, and there entrapped. Periodic cleaning of the scrubber is easily accomplished by using a vacuum cleaner on the dust contaminated surface. "Similarly it has been found that the application of a vacuum cleaner to the exterior surface of the removable filter will remove considerable dirt and dust, not-'- withstanding the fact that the fibers of the filter have been coated with adhesive. The filter will, however, require periodic replacement or thorough cleaning, and my ventilator is adapted to perrnit removal of the filter for thispurpose without difficulty. Under normal conditions it will not be necessary to replace the hairy felt-like material as a vacuum cleaner will completely remov substantially all dirt and dust adherin to its sur face.

It is, of course, essential that no dust be permitted to leak into the room around the filter or ventilator or other parts of the window. The meeting rails of the sash are, therefore, provided with gaskets of ordinary design to preventthe entry of dust, and where necessary, joints in my ventilator are provided with gaskets for the same purpose.

Fig. illustrates a modification of my ventilator particularly adapted for use in locations where storm windows are desirable. This modification is illustrated in connection with an ordinary wooden double hung window having a lower sash rail 56, a stool 51, and a sill 58 of ordinary con-- struction. A storm window having a lower sash rail 59 is also provided. Th frame for my ventilator in this instance is formed approximately in the shape of a box having open sides, generally designated 69. The bottom of the box slopes, the slope corresponding to the slope of the sill 58. The filter I1 is received by an H shaped member comprising an outer vertical flange 6|, a transverse intermediate web '62 having a drain hole 63, and an inner vertical web 64. The vertical end members of the box are provided with aligned vertical flanges forming, in conjunction with the channel defined by the flanges 'Bi and 64, a receiver for the filter. The lower frame member is attached by any suitable means to the sloping lower side of the box 60, the box being held in position within the window by screws 66 extend-- inlg gsgirough the lower side of the box 60 to the s1 The top of the box designated 61 is permanently attached to the side members, with the exception of a section lying directly above the filter ll. The section 15 is attached to the top member 61 by a piano hinge 80, and has upon its inner edge a downwardly extending flang adapted to fit over the filter H.

The lower sash rail 56 of the window, and the lower sash rail 59 of the storm window rest upon the top of the box 60. Gaskets 68 are, therefore, provided to prevent the leakage of dust or dirt into the room between the ventilator and the sash. One of these gaskets is attached to the outer edge of the upper member 61 directly beneath the lower sash bar 59 of the storm window, and the other gasket is attached to the movable section I5 directly beneath the lower sash rail 56 of th lower sash.

The outer side of the box 60 is covered with a screen 69 which may suitably be of a type known as Koolshade, consisting essentially of a series of flat horizontal bars held in spaced parallel relation by intertwining vertical connecting wires. A screen of this nature effectively prevents the entrance of a considerable portion of the radiant heat of the sun and will cooperate with the filter which, in itself, has considerable insulating value to prevent the introduction of excessive heat into the room.

A scrubber generally designated H is positioned within the box between the screen '69 and the outer side of the filter H. The scrubber may consist of a rigid panel 12 attached to the sides and bottom of the box El], and an outer covering 13 of loosely woven hairy felt-like materialsimilar to that used on the scrubber 44, but in this instance relatively small openings 14 are provided through the covering and the rigid panel. The height of this scrubber is less than the height of the box thereby defining an air passageway between the top of the scrubber H and the upper side 61 of the box. The greater portion of the air entering through the screen 69 will strike the surface of the scrubber and deposit thereon a considerable portion of its dust. After striking the scrubber H most of the air will pass over the scrubber through the passageway, defined by the scrubber and the top of the box, into the filter I! while other portions will pass through the small openings I4 directly into the space between the scrubber H and the filter Two advantages are gained from the use of the small openings [4, namely, a reduction in the resistance to the passage of air, and, secondly, increased cleaning e-fliciency. With regard to the first advantage obtained it may be seen that if air is passed over the scrubber at any considerable velocity a partial vacuum may be formed between the filter and the scrubber, particularly near the bottom of the ventilator, the action of the scrubber being similar to that of a sail. The provision of the openings permits sufficient air to pass through the scrubber to ef fectively prevent a formation of such a vacuum. In addition, many of the fibers, forming the hairy felt-like material used to cover this scrubber, are laid down substantially parallel to the surface of the material with the fiber ends extending outwardly into the openings in irregular formation. Thi produces what I term an end effect which is actually an increase in the scrubbing efficiency of the material and is probably due to the type of surface exposed. The air passing through these openings will be more thoroughly cleaned than that simply passing over the scrubber. The balance of the construction of this modification. of my invention is similar to that described in connection with Fig. 1, it being noted, however, that a water shed Hi is provided by allowing a portion of the upper side 61- to extend outwardly beyond the screen 69.

Fig. 6 illustrates a modification of my device adapted to clean both the fresh air introduced through the filter, and recirculated air drawn upwardly by convection currents. This modification of my device is illustrated as being applied to a window similar to that employed in connection with Fig. 5, like numerals being used to designate like parts. The filter in this instance is supported in part by a lower frame member having an H shaped cross-section comprising a vertical outer flange member ll, a horizontal intermediate web '55 having a drain hole '59, and a vertical inner flange 8|. The lower portion of the flange I? is turned outwardly and provided with openings for screws 82 by means of which the filter is secured to the window. End mem bers similar to those shown in Fig. 2 may be attached to the extremities of the lower frame member to define a receiver for the cartridg type filter I! or flanges may be formed on side plates 92 if desired. A metal plate 83 extends inwardly from the lower frame member parallel to, and resting on the window sill 51, and is provided on its outer edge with a series of lugs '55 having aligned transverse openings. A rod 84 extends through these openings and supports a scrubber 86, which consists of an inner panel 8'! of rigid material, and a covering 88 of hairy felt-like material applied to both sides of the rigid panel. An upper framemember 89 is provided extending inwardly parallel to the lower member 83, the outer edge of this member being curved upwardly as indicated at El. The ends of this member are attached to side plates 92, the distance between members 83 and 89 being slightly greater than the height of the filter H.

A flap 18 positioned directly above the filter I1 is attached to the upper member 89 by a piano hinge 85. The outer edge of the flap It extends outwardly and downwardly forming a water shed. The length of the flap T6 is in excess of the length of the filter I'l, thereby permitting the filter I! to be easily removed.

The side plates 92 extend outwardly beyond the extremities of the members 89 and '83 and are joined at their extremities by an inwardly sloping side 94. The upper edge of the sloping side 94 is located somewhat below and inwardly from the inner edge of the member 89 defining an opening 90. The upper edge of the side 94 is provided with a series of lugs having aligned transverse openings. A rod 96 extends through these openings and supports a scrubber 9'! comprising a rigid panel 98 and covering 99 of hairy felt-like material. The covering 99 is provided only on the side adjacent to the scrubber 86. The lower extremity of the scrubber 91 is turned inwardly as designated at llil. Side walls 92, as well as the inner side of the upper member 89 and the inner side of the lower member 83, are also covered with hairy felt-like material.

The rods 84 and 96 extend beyond the side plates 92 and are threaded at one end and provided with nuts I02 and washers I03, The other end of these rods are bent to form a handle I04, the extremity of which is curved inwardly against a side plate 92, The extremity of the handle I04 is held in contact with the side plate 92 by the resiliency of the rod, the pressure of the handle against the side plate being adjustable by movement of the nut I02. corrugations may be provided in the side plate to cooperate with the extremity of this handle thereby providing means of fixing the scrubbers 86 and 91 in any desired position.

With the scrubbers in the position shown in Fig. 6 fresh air may enter through the filter l1 and pass into the room through the opening 90. Any fine particles of dust or dirt passing through the filter will be removed by the hairy felt-like material covering the interior of the frame and the surface of the scrubber 86, The passage of air into the room, as well as the normal convection currents existing therein, will cause the recirculation of room air upwardly between the scrubber 9'1 and the scrubber 86. Dust particles entrained in this rising column of air will be removed by the action of the felt-like covering of the scrubbers, thereby permitting a cleaned mixture of fresh and recirculated air to emerge from the ventilator.

The adjustability of the two scrubbers permits an infinite range of adjustments, for it may be seen that fresh air may be totally excluded by moving the scrubber 86 into contact with the upper member 89 or recirculation of room air may be prevented by moving the scrubber 91 outwardly in contact with the window sill 51. Greater efficiency in recirculating the air will be had if the ventilator is positioned over a radiator (shown in outline at I06) The material from which the rigid panel forming part of the movable scrubber is made is ordinarily of minor importance except when used in a device similar to that illustrated in Fig. 1. It is often desirable that a small amount of soft light be allowed to pass through the ventilator, as in a hospital room. This may be accomplished by forming the rigid panel of glass and attaching only a very thin layer of the hairy felt-like material to the inner surface thereof. It has been found by experiment that a certain amount of soft light will come through the: filter and a portion of this light will be transmitted by the feltlike material through the glass into the room, and also reflected upwardly by the felt-like material. The light thus produced is very soft and not objectionable to a patient.

The foregoing detailed description has been made in compliance with section 4888 of the Revised Statutes but as many minor modifications may be made without departure from the true spirit and scope of my invention I do not wish to be limited except by the scope of the appended claims.

I claim:

1. In a window ventilator a frame comprising a box of rectangular cross-section having an air inlet and an air outlet, 2. screen in the air inlet, a filter in the outlet removably retained in a vertical position by a frame, a movable scrubber associated with the filter, a fixed scrubber interposed between the screen and the filter, said fixed scrubber comprising a section of rigid material covered with a hairy felt-like material.

2. In a window ventilator a box of substantially rectangular cross-section having an air inlet and an air outlet, a filter in the air outlet, a scrubber hingedly associated with the filter and a fixed vertical scrubber interposed between the air inlet and the filter, said scrubber being perforated at frequent intervals.

3. In a window ventilator a box of substantially rectangular cross-section having an air inlet and an air outlet, a filter supported in the air outlet and scrubbers associated with the filter, one of said scrubbers being movable with respect to said filter and the other of said scrubbers being interposed between the air inlet and. the filter, said last mentioned scrubber being perforated and rigidly attached to the box.

4. In a window ventilator a box of substantially rectangular cross-section, attached to a drainboard and extending outwardly to the extremities thereof, and having an air inlet and an air outlet, a filter supported in the air outlet, and scrubbers associated with said filter, one of said scrubbers being movable with respect to said filter and adapted to control the amount of air passing through the fitler and the other of said scrubbers being interposed between the air inlet and the filter, said last mentioned scrubber being perforated and rigidly attached to the box.

5. In a window ventilator of the type having a frame and an inclined panel secured thereto to deflect the air stream, the combination therewith of a low air impedance filter of fibrous material adapted to be removably supported by the frame in an air inlet, and an air scrubbing meanscomprising a layer of hairy felt-like material attached to the inner side of the panel, said filter and frame being so arranged that air entering through said filter will be directed upwardly across said scrubbing means for scrubbing said air.

6. In a window ventilator, a box-like frame having fresh and room air inlets and an air outlet, the fresh air inlet being on one side and the room air inlet and the air outlet being on the bottom and top respectively and near the other side, a cartridge type air filter in the frame between the fresh air inlet and the air outlet, an adjustable scrubber comprising a rigid panel covered on both faces with a hairy felt-like material and extending from the inner edge of the room air inlet to the air outlet, and a second adjustable scrubber comprising a rigid panel covered on one face with a hairy felt-like material and extending from the outer edge of the room air inlet to the outer edge of the air outlet.

7. In a window ventilator, a frame having bottom and top and side members defining an air passage, an air filter cartridge extending across said air passage, 2, panel extending up from said bottom member and across the outlet of said air passage, and a layer of hairy felt-like material on the side of said panel facing said air passage, said panel being at least slightly larger than said outlet and being mounted for swinging about its lower edge, whereby said panel may be swung away from said outlet to serve as an air deflector with said layer of material serving as an air scrubber, and whereby said panel may be swung against said outlet to close said passage.

8. In a window ventilator, a frame adapted to be placed in a partially open double-hung window and having top, bottom and side members defining an air passage leading in from the outside to the inside of the window, said side members projecting in beyond said top and bottom members, an upright panel extending up from the inner edge of said bottom member, said panel being movable about an axis adjacent to said edge for controlling the efiective size of the outlet of said air passage, and a second upright panel located between and supported by the inwardly projecting ends of said side members, said second panel being adjustable about an axis substantially parallel to said first axis for controlling currents of air rising past said outlet.

9. In a window ventilator, a frame adapted to be placed in a partially open double-hung window and having top and bottom members defining an air passage leading from the outside to the inside of the window when the ventilator is in place, an upright panel extending up from the inner edge of said bottom member and movable towards and away from the inner edge of said top member for controlling the effective size of the outlet of said air passage, a second upright panel, and means for supporting said panel inwardly of and spaced from the inner edges of said top and bottom members, said second upright panel being adjustable for controlling currents of air rising past the outlet of said passage.

10. In a window ventilator of the type having a frame with an opening therethrough and a rigid panel hinged to the frame at one side of said opening, the combination therewith of a low air impedance filter of fibrous material removably supported by the frame in said opening, an

air scrubber consisting of a layer of hairy feltlike material attached to the side of the panel facing said opening, the panel being larger than the opening and movable toward the filter to a position against the frame substantially closing said opening to prevent the passage of air through the ventilator or movable to a position spaced from said frame, and means for causing air passing through said filter to pass upwardly over said scrubber for scrubbing said air.

11. In a window ventilator and air cleaner device, a frame defining an air passage, a low air impedance filter supported by the frame in the air passage, a panel hinged to the frame, means cooperating with said filter and panel for forming a settling chamber into which the air passes from said filter, means for adjusting said panel for forming an outlet of varying size for said air flowing from said chamber or for closing said chamber, and a layer of hairy felt-like material on said panel and having an irregular surface for removing dust particles from the air passing along said panel, whereby air passing through said filter will have its velocity checked in said chamber for settling the dust from said air and will retain dust from said air flowing over said irregular surface.

12. In a ventilator adapted to be inserted in a window opening beneath a partially open window in a building, an air filter within said opening for filtering air entering the building through said opening, a panel inwardly of said filter and inclined inwardly toward its upper end, and an air scrubber comprising a layer of hairy felt-like material on said panel whereby air entering through said opening will first pass through said filter for removing dust therefrom and then along said scrubber for removing impalpable particles of dust passing with the air through said filter.

13. In a ventilator adapted to be inserted in a window opening beneath a partially open window in a building, an air filter within said opening for filtering air entering the building through said opening, a panel inwardly of said filter and hinged at its lower edge to swing its upper edge toward and from said filter, means for holding said panel in adjusted position, an upwardly extending front panel spaced from the first-named panel to provide a passage through which heated air may flow upwardly therethrough, and feltlike material on the outwardly facing surfaces of both of said panels for scrubbing the air flowing over the same.

JOHN L. MOHUN. 

